Pet food manufacturers continually try to improve dry pet foods to make them more nutritious and taste better. Dry pet foods are typically extruded using heat and pressure to make nutritionally balanced, low moisture pellets (kibbles) that are shelf-stable. Unfortunately, these dry kibbles can often be bland-tasting to the animal, so manufacturers usually coat the kibbles with a fat or a palatant to improve the flavor.
Various techniques have been used to coat low moisture kibbles, including drum coaters, pan coaters, and various types of mixers. While these techniques can be somewhat effective, they often have the disadvantage of applying the coating unevenly to the kibbles. That can be particularly true when the coatings are small percentages by weight of the kibbles. Some of the coating may not even stick to the surface of the kibbles, which can become expensive when these coatings are high value materials such as vitamins, flavorings, or nutraceuticals. Additionally, on a large manufacturing scale, large masses of kibbles moving around inside of coaters and mixers can result in abrasion of the kibbles causing the production of fines and even scraping off the coating that was just applied. To help overcome these problems, however, it has now been found that coating low moisture kibbles in a vibrating conveyor under conditions that ensure particle mixing in the bed can assist in providing better application of the coating among the kibbles and can reduce the losses associated with less efficient coating machinery by providing a gentler method of handling and coating the kibbles.